<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <title>基础选择器</title>
  <style>
    * {
      margin: 0;
      padding: 0;
      color: blue;
    }

    .box1 {
      color: pink;
    }

    .box3 {
      color: red;
    }
    span {
        font-size: 30px;
    }
    .c1 {
      color: skyblue;
    }
    /*复合选择器, 选中满足复合条件的元素*/
    span.c1 {
      color: green;
    }
  </style>
</head>

<body>
  <!--
  行内 id class 元素 样式继承
-->
<div class="box1">this is div</div>
<span class="c1">c1 span</span>
<div id="box2">this is div</div>
<span>element span</span>
<div class="box3">this is div</div>
</body>

</html>